Topological Repairing of 3D Digital Images

We present here a new randomized algorithm for repairing the topology of objects represented by 3D binary digital images. By “repairing the topology”, we mean a systematic way of modifying a given binary image in order to produce a similar binary image which is guaranteed to be well-composed. A 3D binary digital image is said to be well-composed if, and only if, the square faces shared by background and foreground voxels form a 2D manifold. Well-composed images enjoy some special properties which can make such images very desirable in practical applications. For instance, well-known algorithms for extracting surfaces from and thinning binary images can be simplified and optimized for speed if the input image is assumed to be well-composed. Furthermore, some algorithms for computing surface curvature and extracting adaptive triangulated surfaces, directly from the binary data, can only be applied to well-composed images. Finally, we introduce an extension of the aforementioned algorithm to repairing 3D digital multivalued images. Such an algorithm finds application in repairing segmented images resulting from multi-object segmentations of other 3D digital multivalued images.

Blogs as Alternative

It has been argued that blogs, as an extension of 1960s 'New Journalism,' have become an important form of alternative media. At their idealized best, blogs can report news without the constraints of censure or the pressures of advertising. This argument suggests that blogs can therefore offer a deeper analysis, based upon a diverse range of sources and contributing citizen commentators, which is not possible through modern corporate, mainstream outlets. This exploratory study uses both critical discourse and content analysis to examine 344 posts, 1,712 hyperlinks, and 10,401 comments from 4 political/current events blogs within a 7-day period. This research argues that previous conceptualizations of alternative media, at least in relation to the political/current events blogosphere, might need reconsideration.     

Digital sound broadcasting: Satellites or Terrestrial Networks?

When European laboratories decided to develop a digital sound broadcasting system (DSB), they specified three main conditions to fulfil:

• quality improvement up to the level of ‘CD’ sound, even in difficult reception conditions (mobile vehicles, etc)
• additional significant digital data transmissions in order to transform sound broadcasting into a really new service
• the possibility of a common system for satellite and terrestrial transmissions.

It is on these bases that the European project ‘Eureka 147’ defined the system called DAB (digital audio broadcasting). In 1992, the ITU Conference WARC 92 allocated 40 MHz to DSB in the L-band in the configuration of complementary terrestrial and satellite networks; nevertheless, the present state of technical possibilities makes such mixed networks almost unfeasible and the lack of available spectrum in VHF bands led a significant number of countries to envisage L-band for T-DAB. The situation could turn to a competition between terrestrial and satellite networks, especially because the bandwidth in L-band is not that large! France belongs to the countries facing this problem. L-band alone is intended to be used by T-DAB, and broadcasters taking part in the work of ‘Club DAB’ estimated that 20 MHz would be a minimum to ensure the success of T-DAB introduction. It is half of the DSB band. Splitting this band into two parts has already been decided by CEPT, but in the proportion of 1/3 for T-DAB. This organization intends to arrange a European planning meeting for T-DAB in July 1995, and, shortly after, several countries are ready to start the implementation of the terrestrial networks. At the same time, international broadcasters wonder whether satellite transmission could present an alternative to HF.     

Hierarchical classification of data streams: a systematic literature review

The classification task usually works with flat and batch learners, assuming problems as stationary and without relations between class labels. Nevertheless, several real-world problems do not assume these premises, i.e., data have labels organized hierarchically and are made available in streaming fashion, meaning that their behavior can drift over time. Existing studies on hierarchical classification do not consider data streams as input of their process, and thus, data is assumed as stationary and handled through batch learners. The same can be said about works on streaming data, as the hierarchical classification is overlooked. Studies concerning each area individually are promising, yet, do not tackle their intersection. This study analyzes the main characteristics of the state-of-the-art works on hierarchical classification for streaming data concerning five aspects: (i) problems tackled, (ii) datasets, (iii) algorithms, (iv) evaluation metrics, and (v) research gaps in the area. We performed a systematic literature review of primary studies and retrieved 3,722 papers, of which 42 were identified as relevant and used to answer the aforementioned research questions. We found that the problems handled by hierarchical classification of data streams include mainly classification of images, human activities, texts, and audio; the datasets are mostly created or synthetic data; the algorithms and evaluation metrics are well-known techniques or based on those; and research gaps are related to dynamic context, data complexity, and computational resources constraints. We also provide implications for future research and experiments to consider common characteristics shared amongst hierarchical classification and data stream classification.

     

High Figure of Merit (FOM) of Bragg Modes in Au‐Coated Nanodisk Arrays for Plasmonic Sensing

Gold‐coated nanodisk arrays of nearly micron periodicity are reported that have high figure of merit (FOM) and sensitivity necessary for plasmonic refractometric sensing, with the added benefit of suitability for surface‐enhanced Raman scattering (SERS), large‐scale microfabrication using standard photolithographic techniques and a simple instrumental setup. Gold nanodisk arrays are covered with a gold layer to excite the Bragg modes (BM), which are the propagative surface plasmons localized by the diffraction from the disk array. This generates surface‐guided modes, localized as standing waves, leading to highly confined fields confirmed by a mapping of the SERS intensity and numerical simulations with 3D finite element method. The optimal gold‐coated nanodisk arrays are applied for refractometric sensing in transmission spectroscopy with better performance than nanohole arrays and they are integrated to a 96‐well plate reader for detection of IgY proteins in the nanometer range in PBS. The potential for sensing in biofluids is assessed with IgG detection in 1:1 diluted urine. The structure exhibits a high FOM of up to 46, exceeding the FOM of structures supporting surface plasmon polaritons and comparable to more complex nanostructures, demonstrating that subwavelength features are not necessary for high‐performance plasmonic sensing.     

Anticipating Cutoff Diameters in Deterministic Lateral Displacement (DLD) Microfluidic Devices for an Optimized Particle Separation

Deterministic lateral displacement (DLD) devices enable to separate nanometer to micrometer‐sized particles around a cutoff diameter, during their transport through a microfluidic channel with slanted rows of pillars. In order to design appropriate DLD geometries for specific separation sizes, robust models are required to anticipate the value of the cutoff diameter. So far, the proposed models result in a single cutoff diameter for a given DLD geometry. This paper shows that the cutoff diameter actually varies along the DLD channel, especially in narrow pillar arrays. Experimental and numerical results reveal that the variation of the cutoff diameter is induced by boundary effects at the channel side walls, called the wall effect. The wall effect generates unexpected particle trajectories that may compromise the separation efficiency. In order to anticipate the wall effect when designing DLD devices, a predictive model is proposed in this work and has been validated experimentally. In addition to the usual geometrical parameters, a new parameter, the number of pillars in the channel cross dimension, is considered in this model to investigate its influence on the particle trajectories.     

Root-restricted Kleenean rotations

We generalize the Kleene theorem to the case where nonassociative products are used. For this purpose, we apply rotations restricted to the root of binary trees.